ISAR imaging is a well known technique which uses range and Doppler information from a radar to generate an image of a moving target. Research performed on the combination of a large receive array with airborne ISAR is scarce. This thesis is aimed to reach the highest possible image quality for AMBER, a radar with a 24 element receive array which was developed by TNO. Optimizing the image quality was split up in two parts, motion compensation and clutter suppression. A literature study is performed to research the existing methods. A performance evaluation is performed on different motion compensation techniques based on a simulation which is set up to resemble the radar parameters of AMBER. Based on the results of this evaluation, keystone formatting combined with image contrast maximization is concluded to be the best fitting approach. For clutter suppression a similar approach is followed with real measured data. Apart from the existing techniques, MVDR, DPCA and ODPCA, a new technique is proposed which filtered a target from clutter based on motion. It is referenced to as the IDPCA. The techniques show better image quality than regular beam forming. To enhance the image quality more, a method is searched to combine different clutter suppression techniques. This leads to a unique method which is proposed in this thesis. The new technique exploits the circular phase variance of pixels in the range Doppler image between different sub arrays. With this approach, strong clutter can be filtered in the range Doppler domain based on its angle of arrival. The newly proposed technique is applied as a mask, as it does not contain amplitude information of the target. Combined with the ODPCA method, the final image is generated. The combination of techniques shows clear improvements from the other discussed approaches. ... Read more

The ZEBRO is a fully autonomous six-legged robot designed for swarm behaviour and is the size of an A4 sheet of paper. However, there does not exist an charging station for the ZEBRO yet. At this time, the battery still has to be replaced manually, which defeats the purpose of an autonomous system. An autonomous charging station has to be designed to complete the system. The charging station can be split into 3 parts: the autonomous charging station, the wireless power transfer, and the battery management system (located in the ZEBRO). In this particular thesis, the autonomous charging station will be discussed.
Since all components in the ZEBRO are built to be modular, the design of the autonomous charging station is chosen to fit this principle. The charging station will consist of one central unit, and several connectable (modular) pads. Each pad will be able to hold and charge a single ZEBRO in 30 minutes.
The charging station contains a communication module to communicate its location to ZEBRO's in need of charging. To calculate the locations of the connected pads, a grid will be created by serial communication between the charging station and the connected pads through Raspberry Pi's. (The pads do not have a communication module and do not have their location defined)
To power the wireless power transfer unit, a power supply of 48V and 500W will be implemented in the charging station. Each pad will consume about 100W, so a maximum of 4 pads can be connected. (Due to power loss). If more pads need to be connected, an additional power supply can be put in parallel.
All separate components have been simulated or tested and do work as predicted. The integration of all components of the charging station was successful as well. At this time, the complete system with the wireless power transfer and battery management system has not yet been put together and so it is unknown if it works as a whole.
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